Fuel Economy Converter
Convert between MPG, L/100km, and km/L instantly.
Quick Reference
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Typical Vehicle Values
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This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Request a ToolHow to Use the Fuel Economy Converter
This converter translates fuel economy ratings between four common units used around the world. Whether you are comparing a European car listed in L/100km to an American rating in MPG, or converting between US and Imperial gallons, this tool handles it all.
- Enter a value. Type the fuel economy number you want to convert. For MPG and km/L, higher numbers mean better efficiency. For L/100km, lower numbers mean better efficiency.
- Choose your units. Select the source unit from the "From" dropdown and the target unit from the "To" dropdown. The result updates instantly.
- Check the reference tables. Below the result you will find a quick-reference conversion table and a table showing typical values for different vehicle types.
- Use swap to reverse. Click the arrow button between the dropdowns to switch the conversion direction.
Note that MPG and L/100km have an inverse relationship. A car rated at 30 MPG (US) uses about 7.84 L/100km. As MPG goes up, L/100km goes down.
About Fuel Economy Units
The United States uses miles per gallon (MPG) based on the US gallon (3.785 liters). The United Kingdom historically uses MPG based on the Imperial gallon (4.546 liters), which means the same car will have a higher MPG number in Imperial than in US units. Most of Europe, Asia, and Australia use liters per 100 kilometers (L/100km), which measures fuel consumption rather than fuel efficiency. Japan commonly uses km/L. This converter handles all four units and correctly accounts for the inverse relationship between distance-per-volume and volume-per-distance measurements.
Frequently Asked Questions
Why is MPG (Imperial) higher than MPG (US) for the same car?
An Imperial gallon is about 20% larger than a US gallon (4.546 liters vs 3.785 liters). Since you can drive farther on a larger gallon of fuel, the MPG number is higher even though the car's actual efficiency is the same. A car rated at 30 MPG (US) is about 36 MPG (Imperial).
How do I convert MPG to L/100km?
Divide 235.215 by the MPG (US) value to get L/100km. For example, 30 MPG equals 235.215 / 30 = 7.84 L/100km. For Imperial MPG, divide 282.481 by the MPG value instead. The relationship is inverse: as MPG increases, L/100km decreases.
What is a good fuel economy rating?
For a gasoline car, 30+ MPG (US) or under 8 L/100km is considered good. Hybrids typically achieve 45-55 MPG (5-6 L/100km). The EPA rates electric vehicles in MPGe (miles per gallon equivalent), where 100+ MPGe is common. The best rating depends on vehicle class, as a fuel-efficient SUV at 28 MPG may be excellent for its category.
Why do some countries use L/100km instead of MPG?
L/100km measures fuel consumption directly, making it easier to calculate trip fuel costs. If you know a trip is 500 km and your car uses 7 L/100km, you need 35 liters. MPG measures efficiency (distance per unit of fuel), which is more intuitive for comparing vehicles but less convenient for cost calculations. Most metric countries adopted L/100km for its practicality.